The effects of this micronutrient in modulating the immune system include the regulation of T cell differentiation and proliferation [85], also helping to regulate the interplay between helper T cells and cytotoxic T cells [95, 137]. It also play a role in IFN-γ production and participates in the production of cytokines, in fact it is involved in the regulation of the production and action of cytokines. It forms highly toxic hydroxyl radicals, involved in the killing of bacteria by neutrophils and it is a component of enzymes critical for the functioning of immune cells (e.g. ribonucleotide reductase involved in DNA synthesis) [95]. The iron-rich state promotes the M2-like macrophage phenotype and negatively regulates the M1 pro-inflammatory response [138]. This nutrient is necessary for the generation of ROS, that kill pathogens (by neutrophils) during the oxidative burst [85]. Finally, it appears to be essential for the differentiation and growth of epithelial tissue [95].